As Bloomberg View reports, there’s a correlation between who knows the most about a product and who buys the (often cheaper) generics.

The researchers looked at seven years’ worth of consumer data and found that expert behavior was markedly different from regular shopper behavior. Pharmacists, for instance, went for the brand-name (also known as “national brand”) medication only 8.5% of the time, while the less knowledgeable shopper went for it 26% of the time.

Similar patterns arose when chefs went shopping for pantry staples like salt and sugar: The brand-name products made up 40% of total sales, but chefs bought only 23%.

It’s interesting that health-care professionals show no special interest in buying store-brand salts, sugars or baking sodas; for those products, their choices look a lot like most other consumers’. And while chefs do show a preference for store-brand headache remedies, it’s not nearly as great as that of health-care professionals. For the most part, people’s knowledge is domain-specific.

It’s also noteworthy that people without a college education were the most likely to shell out for brand-name products, although the study didn’t draw conclusions on that point.

The takeaway is simple: Those who know best tend to bypass the brand names for a likely less expensive alternative — so we, the “average consumers,” might be wise to do the same.